1. Field of the Invention
The present invention relates to an ultrasonic washing apparatus, and, more particularly, to a domestic injection-type ultrasonic washing apparatus which is designed to ultrasonically vibrate and inject inlet raw water to thereby wash fruits, vegetables, dishes, etc.
2. Description of the Related Art
In general, an ultrasonic washing technique mainly utilizes cavitation induced by ultrasonic energy, particulate atomization, or acceleration of water particles.
The cavitation is a phenomenon that fine bubbles are formed and collapsed under the influence of an ultrasonic pressure when ultrasonic energy is propagated in a solution, resulting in shock waves with high pressure and temperature. The resulting shock waves enable even deep interior portions of an object, immersed in the solution, to be washed within a short time. Actually, in addition to the shock energy caused by the cavitation, agitating action caused by a radiation pressure of ultrasonic waves, thermal action, etc. induce synergism with detergent, resulting in outstanding washing effects.
When the ultrasonic energy is applied to running water streams, further, an acceleration force of water particles is increased by capillary waves. Using the increased acceleration force enables washing of minute particles, such as agricultural medicines or foreign substances adhered to the object being washed. Furthermore, the ultrasonic washing technique is effective to eliminate the recontamination risk of the washed object, and to minimize damage to the object being washed. For this reason, the ultrasonic washing technique has been conventionally applied in the precision washing of semiconductors, etc.
Recently, to more completely remove foreign substances adhered to fruits, vegetables, or dishes (hereinafter, referred to as “object being washed”) with a reduced amount of water, domestic injection-type ultrasonic washing apparatuses, which are designed to ultrasonically vibrate wash water being injected, have been developed.
The injection-type ultrasonic washing apparatuses comprise an oscillator device in which ultrasonic vibrators and various elements to oscillate the ultrasonic vibrators are mounted, and an injector device to ultrasonically vibrate and inject inlet raw water. Based on whether the oscillator device and the injector device are integrally formed with each other or are separated from each other, the injection-type ultrasonic washing apparatuses are classified into integral-type ones and discrete-type ones.
FIG. 1 is a schematic sectional view illustrating an injection-type ultrasonic washing apparatus having a discrete structure according to the prior art.
As shown in FIG. 1, the injection-type ultrasonic washing apparatus 10 of the prior art having a discrete structure comprises a housing 11 containing various elements therein, an ultrasonic oscillation circuit unit 16 to generate electric vibration, an ultrasonic vibrator 12 to convert the high-frequency electric vibration into mechanical vibration, an input cord 13 to which exterior power and operating signals are applied to drive the ultrasonic vibrator 12, a protector 15 to prevent breakage of a coaxial cable 14 of the input cord 13, a gasket 19 fitted around the ultrasonic vibrator 12 to prevent leakage of wash water from a water reservoir 21, a metal plate 17 used as a terminal to transmit the power from the ultrasonic oscillation circuit unit 16 to the ultrasonic vibrator 12, a heat sink 18 to absorb heat generated in the vibrator 12, a raw water inlet portion 20 to introduce raw water, i.e. wash water, from an exterior source into the water reservoir 21, the water reservoir 21 serving to store a predetermined amount of the raw water sufficient for concentrative irradiation of ultrasonic waves, and an injection nozzle 22 to inject the ultrasonically vibrating wash water.
In the above-described injection-type ultrasonic washing apparatus 10 having a discrete structure, the oscillation circuit unit 16 is separated from an oscillator device 25, requiring a separate mounting space therefore.
The greater the distance between the oscillation circuit unit 16 and the oscillator device 25 is, the greater the deterioration in the transmission of driving voltage and driving signals. This results in low oscillation efficiency in spite of the use of the coaxial cable, and increases manufacturing costs of the washing apparatus.
FIG. 2 is a schematic sectional view illustrating an injection-type ultrasonic washing apparatus having an integral structure according to the prior art.
As shown in FIG. 2, the injection-type ultrasonic washing apparatus 30 having an integral structure comprises a main passage 31 to guide raw water introduced from a raw water inlet portion 39, branch passages 32 diverged from the main passage 31 to guide the raw water into a plurality of injection nozzles, the injection nozzles 33 designed to temporarily store the raw water and to inject it to the outside, ultrasonic vibrators 34 to apply an ultrasonic vibrational energy to the raw water, one or more gaskets 35 provided between the ultrasonic vibrators 34 to prevent leakage of the raw water, an oscillation circuit unit 36 containing various elements therein to produce driving signals required to drive the ultrasonic vibrators 34 upon receiving exterior power, buffers 37 provided between frictional surfaces of the injection nozzles 33 and a housing 38, and a power line unit 40 to transmit the driving signals from the oscillation circuit unit 36 to the ultrasonic vibrators 34.
The power line unit 40 includes a coaxial cable 41 to attenuate vibration of the ultrasonic vibrators 34, an insulation cap 42, and a spacer 43 to adjust a distance between the coaxial cable 41 and the insulation cap 42 while supporting the coaxial cable 41.
The above-described injection-type ultrasonic washing apparatus 30 having an integral structure has the following problems.
Firstly, although the oscillation circuit unit 36 is integrally provided in the washing apparatus 30 to thereby eliminate the necessity of a separate mounting space thereof differently from the discrete-type ultrasonic washing apparatus 10, it excessively increases the volume of the washing apparatus 30, making it difficult to mount the washing apparatus 30 to a general domestic sink.
Secondly, the oscillation circuit unit 36 is remote from the ultrasonic vibrators 34, still requiring the use of the coaxial cable 41 to attenuate the vibration of the ultrasonic vibrators 34.
Thirdly, since the branch passages 32 to supply the raw water to the injection nozzles 33 are arranged on a lateral side of the injection nozzles 33, a vortex is generated in the injection nozzles 33, making uniform transmission of ultrasonic vibrational energy impossible. This causes bending of water streams injected from the injection nozzles 33, resulting in a reduction in the transmission distance of the vibrational energy.
Fourthly, the oscillation circuit unit 36 has no radiation function, and also has a complicated structure, suffering from a difficulty in repair and exchange of damaged oscillator and injector devices thereof.